Disorders Of The Excretory System
- Kidney Failure: Malfunctioning of kidneys
can lead to accumulation of urea in blood,
a condition called uremia, which is highly
harmful and may lead to kidney failure. In
such patients, urea can be removed by a
process called hemodialysis.
Blood drained from a convenient artery is
pumped into a dialysing unit after adding an
anticoagulant like heparin. The unit contains
a coiled cellophane tube surrounded
by a fluid (dialysing fluid) having the same
composition as that of plasma except the
nitrogenous wastes.
The porous cellophane membrane of the tube
allows the passage of molecules based
on concentration gradient. As nitrogenous
wastes are absent in the dialysis fluid, these
substances freely move out, thereby clearing
the blood. The blood is pumped back to the
body through a vein after adding anti-heparin
to it. - Renal Calculi: Stone or insoluble mass of
crystallised salts (oxalates, etc.) formed
within the kidney. These produce severe pain
if they result in obstruction of urethra.
Smaller sized calculi or stones are expelled
by the body, while larger ones require
surgical procedure to be expelled.- Uremia: Malfunctioning of kidneys due to
accumulation of urea in blood. It is very
harmful and leads to renal failure. For such
kind of patients we go for hemodialysis - Glomerulonephritis: Inflammation of
glomeruli of kidney.